(Help) Computer stuttering only in Games

[Aizen2k25]

Good evening, everyone. How are you doing?
I'm experiencing severe FPS drops. It's not a smooth drop from 60 to 58, but a sudden, noticeable freeze for a microsecond. I didn't have this issue before when I was using integrated graphics and a much weaker motherboard. However, I have run many tests and will list EVERYTHING I’ve tried below. Please check everything—I have even tried the obvious solutions.

My setup:​

• CPU: Ryzen 5 4600G
• GPU: RX 6600 Asrock Challenger
• Motherboard: MSI B450M Pro VDH Max
• RAM: 2x8GB T-Force 3000MHz
• PSU: Corsair CV650
• SSD: Crucial BX500 (System + Minecraft)
• NVMe SSD: Lexar MN620 512GB M.2 (Games)
• Monitor: LG Ultragear 144Hz FreeSync

For some reason, not all games behave like this. Just Cause 3 and The Witcher 3 run fine, but games like Left 4 Dead 2, GTA V/Online, and Minecraft 1.8.9 (I like that version) experience FPS drops in different ways.

• Minecraft 1.8.9: Opening the inventory drops my FPS by about -10. For example, from 144 to 134, sometimes more, sometimes less, but always in a sudden way. Hitting a mob, entering water, and even unlocking achievements like collecting wood also cause FPS drops. This ruins my experience since my PC should easily handle a 10+ year-old version of the game.
• GTA V: The FPS drops randomly, but cutscenes cause aggressive FPS dips, and there are stutters in random scenarios, even on lower settings.
• Left 4 Dead 2: The game freezes randomly during matches, making the first few minutes frustrating.

I have tried so many things—you have no idea how much time I have spent trying to fix this. Below is everything I have tested so far:

What I have tried:​

• Swapped my PSU with a friend’s working PSU
• Tested RAM sticks one by one
• Ran MemTest (no errors found)
• Enabled/Disabled XMP
• Disabled Dual Channel
• I tried a different memory
• Lowered RAM clock to JEDEC standards and tested below 3000MHz
• Switched back to my old motherboard + fresh Windows installation
• Bought a new mouse and lowered DPI
• Undervolted the CPU
• Enabled/Disabled PBO
• Enabled/Disabled fTPM
• Enabled/Disabled Virtualization
• CPU & GPU temperatures are below 70°C
• Enabled/Disabled the integrated GPU
• Fresh Windows installation without the RX 6600
• Swapped RX 6600 for a GTX 1050 Ti (Used DDU)
• Undervolted RX 6600
• Tried multiple RX 6600 driver versions (Used DDU each time)
• Enabled/Disabled FreeSync
• Enabled/Disabled 4G Decoding & Resizable BAR + SAM
• Installed only the GPU driver without Adrenalin Software
• “Optimized” Windows
• Installed Windows 11
• Installed Windows on another SSD and also on the NVMe M.2
• Enabled/Disabled HPET
• Enabled/Disabled MPO
• Enabled/Disabled Core Isolation in Windows 11
• Enabled/Disabled Windows Firewall
• Disabled all overlays (Discord, Adrenalin, Steam, etc.)
• Disabled Steam Cloud
• Limited FPS (60/70/144...)
• Increased pagefile size
• Updated and downgraded BIOS multiple times
• Ran GPU stress tests
• Reduced latency using LatencyMon
• Lowered graphics settings in games
• Enabled/Disabled V-Sync / Enhanced Sync
• Disabled background programs
• Disabled unnecessary Microsoft services
• Enabled/Disabled Memory Tick
• Ran games in windowed mode
• Checked for high RAM/Disk usage
• Monitored background processes (only Microsoft or essential drivers running)
• Updated chipset, audio, and network drivers
• Enabled High Performance Mode in Power Settings
• Enabled Ryzen High Performance Mode in Power Settings
• Enabled Balanced Power Mode
• Disabled PCI Express power saving mode
• Disabled HDD sleep mode in Power Settings

Minecraft-specific attempts:​

• Tried newer versions of Minecraft (same issue occurs)
• Tried different Java versions

Honestly, I don't know what else to do. I'm exhausted. This is not normal. I did not have these issues before, even using integrated graphics. If this happened in every game, it would make more sense, but the fact that Minecraft is affected proves that something is very wrong.
I’m really frustrated at this point—I’ve practically rebuilt my PC, yet I’m dealing with more issues than fun.
If you have experienced this before or have any other suggestions, please let me know. Every failed attempt just makes me more frustrated.

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